1. Field of the Invention
Exemplary embodiments of the present invention relate to a three dimensional shape measurement apparatus and a method of measuring a three dimensional shape. More particularly, exemplary embodiments of the present invention relate to a three dimensional shape measurement apparatus and a method of measuring a three dimensional shape capable of reducing measurement time.
2. Discussion of the Background
Generally, a three dimensional shape measurement apparatus measures a three dimensional shape of a measurement target by using a photographed image. The three dimensional shape measurement apparatus may include a projecting section illuminating light to the measurement target, a camera section photographing an image by using the light reflected by the measurement target, and a control section controlling the projecting section and the camera section and arithmetically processing the image to measure the three dimensional shape.
As described above, since the three dimensional shape measurement apparatus arithmetically processes the photographed image of the measurement target to measure the three dimensional shape, reducing measurement time for the three dimensional shape of the measurement target enhances rapidity and efficiency of work, to thereby reduce measurement cost. Thus, the measurement time is very important factor.
In a conventional three dimensional shape measurement apparatus, the following examples may be factors increasing the above mentioned measurement time.
First, the measurement time increases according to a photographing method and a grating-moving method.
FIG. 1 is a block diagram illustrating a method of measuring a three dimensional shape using a conventional three dimensional shape measurement apparatus.
Referring to FIG. 1, when using two projecting sections, conventionally, a plurality of images is photographed while a grating of a first projecting section is moved, and then a plurality of images is photographed while a grating of a second projecting section is moved.
However, since a grating is moved after photographing of camera, photographing time and movement time of the grating are independently required. Thus, total measurement time increases, and more increases as the number of the projecting sections increases.
Second, when a measurement target having a relatively large area is divided into a plurality of measurement areas and measured, long measurement time is required.
In case that images are photographed for each measurement area with respect to the measurement target having a relatively large area, and a three dimensional shape of the measurement target is measured by using the images, it is required that the camera section photographs an image for any one measurement area, and thereafter the image is arithmetically processed to measure a three dimensional shape in the measurement area.
However, in case that arithmetical process for the photographed image becomes a little longer, it may take a long time that a measurement target area is moved to each measurement area of the measurement target and in addition, the three dimensional shape measurement apparatus measures three dimensional shapes of all the measurement areas.
Third, it is limited to reducing photographing time of a camera and moving time of a grating element.
In order to rapidly inspect a board, it is required that photographing time of a camera and moving time of a grating element is reduced. However, when photographing time of a camera is reduced, a reflection grating image is not sufficiently received to thereby prevent accurate inspection. In addition, moving time of a grating element is very limited. Thus, it is difficult to substantially reduce inspection time.
Fourth, in case that a measurement target has a relatively small size, measurement time needlessly increases.
In order to inspect a measurement target having a relatively small size, for example, an LED bar, a plurality of measurement targets is inspected in a status that the measurement targets are mounted on an inspection board such as a jig. Thus, both a portion in which the measurement targets exist and a portion in which the measurement targets do not exist are in a field of view of a camera.
Accordingly, when image data are acquired for all the areas in the field of view of the camera, and the image data are processed, unnecessary data process is performed for the portion in which the measurement targets do not exist, to increase data processing time and thereby increase measurement time.